<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="https://cdn.staticfile.org/vue/2.4.2/vue.min.js"></script>
</head>
<style>
    .div1{
        width: 200px;
        height: 200px;
        background: pink;
    }
    .div2{
        width: 100px;
        height: 100px;
        background:plum;
    }
    .div3{
        width: 50px;
        height: 50px;
        background:purple;
    }

</style>
<body>
    <div id="app">
    <div class="div1">
        <div class="div2">
            <div class="div3">
                
            </div>
        </div>
    </div>

    </div>
    <script>
        var vm=new Vue({
           el:'#app',
           data:{},
           methods:{}
        });
    </script>
</body>

</html>